diesel soot covering

[kjg1951]

I have a 1994 28t Albin ... We went on a cruise the past 5 days down to Wrightville beacn NC from New Bern NC ... the problem we experienced was that we were covered in diesel soot as well as all our gear and in the salon. Has anyone been able to figure out how to prevent this back draft from happening ... I am sure our lungs have the same coating as everything else on the boat. I have used Valtech as an additive.... which before the transom was just black after a 3 hour cruise, and now it is much better...Thanks for some thought son this subject...
Kevin g
New Bern N.C.

[DougSea]

Is this a new condition? Black smoke/soot can be made worse by lack of combustion air. Was something blocking the engine air inlets? Meaning not just the engine and it's turbo "filter", but the various under gunnel air vents.

[jleonard]

You can make an extension to get the exhaust away from the transom a little bit and that will help. I have also seen some put a 45 deg extension to put the exhaust stream to the outside.
However look at the items Doug listed to minimize the soot first. Soot/black smoke is indicative of incomplete combustion.

[kjg1951]

Doug .... I will check but I am pretty sure they are clear ... I did put some screening between the vents as I was getting bees in ... Could that be enough to lessen the air flow ?

[kjg1951]

I did notice that the port side vents are facing towards the bow and the starboard side are facing towards the stern ... Any thoughts ?

[DougSea]

It's unlikely the screening has caused a problem unless it's now clogged with some sort of debris. And the vents facing different directions is pretty standard.

Is the screening the only change? Did you start storing stuff under the deck hatches that wasn't there before? Seal up any openings to cut down on noise?

Do you see smoke/soot while underway at cruising speed? If so, get a helper on board and open the engine hatch while running. If the smoke lightens you have an air feed issue. If not you may have a cylinder running rich (too much fuel).

You didn't comment on whether or not the problem is new. If it IS new and you haven't done anything to hinder combustion air flow I'd get a mechanic on board to look things over.

Good luck!

[kjg1951]

I have been having the problem on and off ... last year on a 3 hour cruise the transom was just covered in black soot ... I put an additive in the fuel Valvtect Diesel guard and seemed to help abit .... I have added some insulation under the deck hatches to cut down on the noise... I do have white vapor coming from the exhaust while under way and on start up when I go to go on plane I do get a puff of black smoke but just for a short time.... it happens when the wind is at our backs .... maybe an extension or a angled out the side may help?? I will try opening the engine cover and see if there is a difference. I also have a Volvo 6 cylinder engine thanks for the help ...

[Russell]

I don't think you should ever get that much smoke. Have you checked to see that the engine can turn the RPM where the horse power is rated at wide open throttle? If the prop is too big or covered with barnacles it will lug the engine and cause smoking. If a previous owner has overpropped the boat in an attempt to get more speed or if you have added a lot of weight you may need to reduce pitch.

[N4QC]

“I did notice that the port side vents are facing towards the bow and the starboard side are facing towards the stern ... Any thoughts ?”

This set up of the vents is to provide air flow into and out of the compartment. Temps in the engine room are to be controlled as well as the amount of fresh air. Air is need for both combustion and heat dissipation.

There are times when the air vents are under sized, and do not allow enough air to do the job, especially when there is a turbo charger in the system. This can lead to a vacuum situation causing a fuel source being suck into the turbo - thus the intake manifold. The extra fuel causes poor combustion resulting in soot. Fuel sources can be from a leaky valve cover, crankcase vent system, and/or leaky high/low pressure fuel lines for the injectors. Poor fuel quality can be another issue.

While under load raise the engine cover. If the rpms of the engine go up, you are not getting enough air into the engine room.

Recommend an inspection of your exhaust system. Check the flange of the joint of the turbo to the wet exhaust mixer as well as all clamps at elbows and muffler points for possible exhaust leaks.

Use a laser thermometer to check your injectors both under load and at idle after a run. Shoot the same spot for each injector. They should all read about the same. A reading way out of whack indicates trouble with that injector.

Jleonard’s and DougSea’s comments are in order…

Clean fuel and adequate clean air make for a clean running diesel…

[Tree]

Yesterday after a pretty rough ride back home (35 miles heading into a northerly 25mph wind) I noticed that we had a slight black film over the stern end of the boat. The vinyl on the bolsters was pretty black and will need a good clean with vinyl cleaner to sort them out but also all the top sides had a film of soot on them.

I am just assuming it was down to the sea conditions and the engine having to work hard that has caused it. One thing I looked at was the inward vents on the boat and noticed they are made from tumble dryer hose? Looks pretty cheap and nasty as the starboard one had collapsed rendering it useless. Any suggestions on what else could be used instead of this hose to better it?

[N4QC]

Tree:

You may want to check out aluminum flexible dryer ducting. The aluminum is replacing the flexible vinyl dryer ducting on this side of the pond…

Have fun,

[Tree]

Good call there Joe, I hadn't even considered it yet I have seen it in DIY stores as the expensive option to normal ducting.

I'll be doing that.